"We will strictly control coal-fired power generation projects", Mr. Xi said, speaking via video link.
The gathering will be focused on themes such as clean energy innovation and the importance of oceans and forests, with speakers including Pope Francis and Bill Gates, the Microsoft co-founder.
Greenpeace UK's head of climate, Kate Blagojevic, said the summit had more targets than an archery competition.
Xi said in December that China would reduce its emissions by 65% from 2005 levels by 2030.
More on the USA announcement: At the White House summit, which will take place virtually on Thursday and Friday, Biden will commit the United States to reducing its greenhouse gas emissions by 50%-52% below its 2005 emissions levels by 2030.
British Prime Minister Boris Johnson called Biden's pledge "a game-changer" that will "have a transformative impact in the global fight against climate change".
Biden's goals to expand jobs and lower greenhouse gas emissions have been met with backlash by Republicans on the Hill who fear high costs to the taxpayer and the destruction of certain industries.
Biden aides said they consulted with unions, educators, activists and businesses before coming up with the goal and believed infrastructure spending could bring an economic boon by creating well-paying jobs.
Pelosi thanks George Floyd for 'sacrificing your life for justice'
I'm just so very, very overwhelmed right now", said Tesia Lisbon, a community activist in Florida's capital of Tallahassee. Biden addressed the nation after telephoning Floyd's family following the verdict , telling them, "We're all so relieved".
It's an urgent but hardly flawless time for the U.S.to try to spur action.
Chinese President Xi Jinping delivers a speech at the Great Hall of the People in Beijing on October 23, 2020.
China's relationship with the United States has sharply deteriorated in recent years but Beijing nonetheless agreed to cooperate on climate during a pre-summit visit by John Kerry, the former U.S. secretary of state who is now Biden's globe-trotting climate envoy.
The emerging US approach is "focusing on what works, and multiple pathways being possible", she said, "and that's something about the USA that I find encouraging". "It's as simple as that". In an apparent veiled remark against the United States last week, Xi said no nation should "arrogantly instruct others and interfere". "'We in India are doing our part", Prime Minister Narendra Modi told participants, adding, "We have taken many bold steps".
Kerry, who was secretary of state under former President Barack Obama, visited Shanghai last week for talks with his Chinese counterpart Xie Zhenhua, becoming the first high-ranking US official to visit China under the Biden administration since its launch in January.
And at home, political divisions exposed by Trump's presidency have left the United States weaker than it was at the 2015 Paris accord.
"There is too much of an impulse in the U.S.to just wish away Trump's legacy and the fact that every election is now basically a coin toss between complete climate denial and whatever actions the Democrats can bring to the table", he said.
Some climate activists have said Biden needs to do even more, however, pointing out that the U.S. is lagging after four years of Trump and the rest of the world has made scant progress to date in cutting emissions, with greenhouse gases already rising again after a dip last year due to pandemic-related shutdowns.